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Author Topic:   panhard bar/j bar question
davis12d
Dirt Roller

Total posts: 5
posted May 02, 2004 07:21 PM  
hey i'm looking for some help deciding what to do to my panhard bar. i'm running a harris 4link/zlink car with a short 15" panhard bar mounted on left side in front of housing and lr spring behind housing and rr spring in front on swingarm. the car has a 200# lr spring and 275# rr. track is dry slick flat half mile. the problem is that the car does a 4-wheel drift to the center of the corner, and lacks bite throughout the corner. i want to know 1. is my short bar hurting performance? 2. how would a j-bar effect performance? we have tried increasing the angle, but found that the car actually snaps to the right when getting off the power. any help would be appreciated.

NJantz
Dirt Forum Champ
Total posts: 755
posted May 03, 2004 08:24 AM  
When you say your car does a 4wheel drift to the center, I'm under the impression that you have a push on entry issue.

Is the car being set before you enter the turn?

What percentages do you have and what are the front spring rates?

You need to swap your rear springs around.

I'm guessing that your not being hooked up from entry to the middle problem is why you don't have any bite through corner exit. To make a 4bar/zlink work, the LR needs to be hiked up and the RR compressed at the middle of the corner. When you generate this type of motion, along with the 4bar's dynamic rollsteer, you generate bite in the back tires. So first I'd be concerned with the handling problem on entry. If you can get the car to enter better, you've got a better chance of it exiting better. so first things first.


[This message has been edited by NJantz (edited May 03, 2004).]

zeroracing
Dirt Forum Champ
Total posts: 1875
posted May 03, 2004 09:51 AM  
how old are the tires, i have had cars 4 wheel drift in the middle bad, with tires that are old(like 15-20 shows) but if you dont have good throttle control it will only take like 5 shows to burn a set of tires up, or less races.
yeah the tires drop off before the 15-20 but i dont notice a large change, just small ones, until abouthere.
go with what njantz and make sure entry is perfect first. if entry is wrong it will ruin exit.

davis12d
Dirt Roller

Total posts: 5
posted May 03, 2004 07:34 PM  
NJantz here is more information on car set up. (no driver in car) cross-51.8% rear-60.6 left-51.5% and right-48.3. I am not setting car before entering turns.(large swepting turns and long straights) Front spring rates are left front 650# right front 750# Tires are new american racer G-60 KK-704's.NJantz I was told that right rear spring has to be stiffer when mounted on swing arm but softer if mounted on bird cage. switching springs around sounds good to me.A friend of ours thats been in racing for many years says he was watching our car all night Sat. night and never seen car get up on the bars the whole night. My son that drives the car has been telling me the same thing.NJantz thanks for your time. I hope you can come up with something that points us in the right direction.

zeroracing
Dirt Forum Champ
Total posts: 1875
posted May 03, 2004 07:58 PM  
add more angle to the short bar to get more roll out of the car to help it hike up. then up your lr spring, and lower your rr.
that would be what i would try first.
....
also 51.5+48.3 does not equal 100.
also lower your rr upper trailing arm, make it at a negitive angle to the back, and then he can burp the throttle to bring the back around some.

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